Pressure vessel

ABSTRACT

The present invention relates to a pressure reservoir comprising a rigid envelope having two ports, a flexible separator in the form of a bladder disposed in the interior of the said envelope and dividing it into two compartments for fluids which are respectively in communication with said ports, the bladder being adapted to move to the vicinity of one of the said ports, which is equipped with a strainer device or screen against which the bladder abuts in operation.

United States Patent 1 Mereier [54] PRESSURE VESSEL [76] Inventor: Jacques H. Mercier, 49 rue de Naples, Paris, France [22] Filed: Oct. 13, 1971 [21] Appl. No.: 188,971

[30] Foreign Application Priority Data Oct. 30, 1970 France ..7039l79 [52] U.S. Cl ..138/30, 92/92 [51] Int. Cl ..Fl6l 55/04 [58] Field of Search ..220/22; 138/30, 39, 40, 41' 210/489; 9.2/92

[5 6] References Cited UNITED STATES PATENTS 3,379,216 4/1968 Mercier ..l38/3O 1 Mar. 27, 1973 Mercier ..l38/30 Mercier ..l38/30 Primary ExaminerSamuel B. Rothberg Assistant ExaminerSteven M. Pollard Attorney-Arthur B. Colvin [57] ABSTRACT The present invention relates to a pressure reservoir comprising a rigid envelope having two ports, a flexible separator in the form of a bladder disposed in the interior of the said envelope and dividing it into two compartments for fluids which are respectively in communication with said ports, the bladder being adapted to move to the vicinity of one of the said ports, which is equipped with a strainer device or screen against which the bladder abuts in operation.

17 Claims, 3 Drawing Figures PRESSURE VESSEL As conducive to an understanding of the invention, it is noted that the screen should have perforations selected in such a way that a free circulation of the fluid will be possible without excessive loss of head, making allowance for the fact that the loss of head resulting from the passage of a fluid through a perforation is a function of the diameter and the depth or height of the perforation. Moreover, the perforations of the screen must be small enough so that when the bladder abuts against the screen there will be no extrusion of the bladder through the perforations with resultant injury to the bladder.

In addition, it is essential that the screen be capable of supporting the load which is transmitted to it when the bladder abuts thereagainst. This load can be substantial, for example, in the order of several tons.

In general, screens associated with pressure vessels do not meet in an entirely satisfactory manner, the set of conditions set forth above. To support the load of several tons transmitted by the bladder, the screen must be thick, which gives the perforations a substantial depth or height and this makes for too large a loss of head, provided the diameter of the perforations is not large. But the choice of a large diameter for the perforations would result in the danger of an extrusion of the material of the bladder into these perforations, with resultant damage to the bladder.

It is among the objects of the invention to provide a pressure vessel of the above type which is of relatively simple construction and may readily be fabricated, which will provide a screen for the oil port of the pressure vessel which will dependably support the end of the bladder abutting thereagainst without likelihood of extrusion and which will provide a high rate of flow with a minimum loss of head.

According to the invention, the screen comprises two superposed plates; a support plate against which the bladder will abut in operation; and a base plate on which the said support plate rests, the support plate being relatively thin and provided with perforations of small diameter, while the said base plate is provided with perforations of large diameter and is convex with the convexity oriented toward the support plate.

As a result of this arrangement, the load transmitted by the bladder, for example of several tons, is received by the thick base plate, while the support plate, due to its small perforations, will prevent extrusion of the bladder. The losses of head are low, both through the base plate, because its perforations, which even if deep, are of large diameter, and through the support plate because its perforations, even if of small diameter, are shallow.

More particularly, the base plate and the support plate are both convex with opposing convexities, and they are applied against one another and rigidly secured at their centers.

According to another feature, the set of two plates is encompassed by and rigidly secured to an annulus or ring member. The base plate rests on a conical or beveled annular surface of the ring providing a seat analogous to a bridge abutment. The base plate can be secured with respect to its bearing zone by immobilization means such as spot welds or the like. The support plate can be crimped in the perimeter of the ring, or fixed in any other manner, for example, by welding.

The screen which is thus composed of the pre-assembled unit formed by the two plates and the ring, is positioned in the oil port of the pressure vessel and releasably secured in place.

According to still another feature, safety means are provided to prevent the screen from being disassem bled accidentally. These safety means may comprise a screw which is adapted to engage with the ring in such a way as to prevent the latter from being disassembled as long as the screw is not removed. This screw can advantageously serve as a drainage screw.

In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention;

FIG. 1 is a general, diagrammatic view of a pressure vessel according to the invention;

FIG. 2 is a detail sectional view on a larger scale of the screen associated with this pressure vessel, and

FIG. 3 is a view similar to FIG. 2 of another embodiment of the invention.

Referring now to the drawings, as shown in FIGS. 1 and 2, the pressure vessel comprises a container 10 of strong rigid material such as steel, cast aluminum or the like, capable of withstanding high pressure and having a pair of ports 13, 14 preferably axially aligned at opposed ends of the container.

The container illustratively has a cylindrical body portion with hemispherical ends 11, 12 through which the ports 13, 14 extend, and has a partition 18 therein, intervening between said ports l3, l4 defining a variable volume chamber 20, 21 on each side. The partition 18 preferably is a collapsible and expansible bladder of resilient material such as rubber or synthetic plastic of like physical characterists, which in distended but substantially unstretched condition is smaller than the cavity of the container 10 and has its longitudinal axis aligned with the ports 13, 14.

The bladder 18 is securely affixed in the container 10, preferably by means of a valve stem 13' affixed to the end of the bladder and extending through the port 13, the stern being located in position by a nut 19.

The valve stem 13' permits introduction of a fluid such as gas under pressure into the chamber 20 defined in the bladder 18 and a cap 15 is provided to cover the outer end of the valve stem 13'.

The port 14 is of relatively large diameter as clearly shown in FIG. 2 and a fluid such as oil under pressure is adapted to flow into said port 14 to charge the chamber 21 and such fluid also discharges from port 14. As illustratively shown in FIG. 2, the port 14 is formed by a tubular sleeve 16 integral with the container and extending axially therefrom, the inner end of sleeve 16 having an inwardly extending annular flange 32 defining a shoulder 32'.

According to the invention, the screen assembly 17 is positioned in port 14. As shown in FIG. 2, the screen assembly 17 comprises two juxtaposed plates, i.e., a relatively thick sturdy base plate 22 which has perforations 23 of relatively large diameter and a relatively thin support plate 24 which has perforations 25 of relatively small diameter.

The base plate 22 and support plate 24 are both convex with opposed convexities and are secured at their central point of contact as by a rivet 26 having rounded ends 27 to prevent injury to the end 18 of the bladder abutting thereagainst.

Encompassing the juxtaposed plates 22, 24, is an annulus or ring member 28 of rigid material, the plates being rigidly secured to the ring member 28.

More particularly, as shown in FIG. 2, the ring member 28 which preferably is of steel, has an annular groove 37 in its outer surface and is of reduced outer diameter at its upper end as at 28'.

The inner diameter of the ring 28 at its outer end 34 is of reduced diameter defining an annular conical beveled abutment surface 29.

As is clearly shown in FIG. 2, the periphery of the curved base plate 22 seats on the beveled surface 29 and is preferably secured thereto as by spot welding at 30. The periphery of the curved support plate 24 is seated in an annular groove 24' in the upper end 28' of ring 28 and retained in place by crimping of said upper end as at 31.

The screen assembly 17 is releasably retained in the sleeve 16. To this end the assembly 17 is inserted into sleeve 16 until the shoulder 35 defined by the reduced diameter portion 28' of ring 28 abuts against annular flange 32. Thereupon, a split ring 33 is positioned in an annular groove 33' in the inner surface of the sleeve 16, said split ring 33 coacting with the outer periphery of the ring 28 to retain the latter in position. Preferably, some play is provided at 35 between shoulder 32' and the adjacent portion of sleeve 28 to permit ready insertion of the retaining ring 33. Preferably, the outer periphery of the outer end of the ring 28 is beveled as at 34 so that when pressure is exerted against the screen assembly 17 by the force of the expanding bladder thereagainst, the ring 33 will be urged into the groove 33' dependably to retain the split ring 33 in position.

Means are provided to prevent removal of the screen assembly 17 while the container is charged with fluid under high pressure. More particularly, if the split ring 33 should be removed when high pressure is present in the container, if the screen assembly was free at such time, it would blow out with great force causing severe injury to the mechanic.

According to a feature of the invention, safety means are provided comprising a screw 36 which is threaded through an associated opening 36' in the sleeve 16 into the annular groove 37 with the inner end of the screw 36 engaging the floor of the annular groove 37 and acting as a set screw. So long as the screw 36 is in position, it is apparent that even if the split ring 33 was removed, the force of the inner end against the floor of the groove 37 would prevent outward movement of the screen assembly 17 and furthermore, the upper annular shoulder defined by the groove 37 would abut against the inner end of the screw 36 if the screen assembly 17 should move outwardly to prevent complete outward movement of said screen assembly.

It is to be noted that the floor of the annular groove 37 is provided with a plurality of perforations 38. Thus, in operation if the mechanic should first remove the split ring 33 without releasing the screw 36, it is apparent that the screen assembly 17 would not be expelled.

If prior to removing the ring member 33, the mechanic should realize that he must first remove the screw 36, he would also realize that he must deflate the expanded bladder 18 to relieve the pressure. If the mechanic does not deflate the bladder 18 but does remove the screw 36, the resulting passageway provided through the perforations 38 and opening 36' in which the screw 36 is positioned will permit bleeding of fluid from the unit to relieve the pressure.

lnthe operation of the unit, gas under pressure is forced through the valve stem 13' to charge the bladder 18. As a result the bladder will expand so that its end 18' comes in contact with the substantially continuous wall formed by the interior of the container 10 and the curved support plate 24. During the course of operation, a fluid such as oil under pressure is forced through the sleeve 16 and through the perforations 23, 25 to charge the fluid compartment 21 thereby compressing the gas in bladder 18. In the normal operation of the pressure vessel, when a valve (not shown) controlling the port defined by the sleeve 16 is opened, the compressed bladder will expand to force the oil out of such port. When the end 18' of the expanded bladder presses against the support plate 24, it will transmit to it a substantial load in the order of several tons. For example, ifthe diameter of plate 24 is in the order of 10 cm. and if the preload on the bladder is in the order of 30 atmospheres, the load is in the order of 2.5 tons. As a result of the arrangement above described, this load is supported by the thick plate 22 supported by the beveled abutments 29. Due to the small perforations 25 in the support plate, the bladder will not extrude so that it will not be injured. The loss of head is low both through the base plate 22 and the support plate 24. This is due to the fact that the perforations 23 in the base plate though relatively long or deep are of large diameter and the perforations 25 in the support plate though of small diameter, are very shallow. As a result of such low loss of head, efficient operation both in filling and in discharge in container 10 is provided.

The embodiment shown in FIG. 3 is similar to that shown in FIGS. 1 and 2 except that the screw 36 is replaced by a screw 36' adapted to close a port 37 in ring 28" and forming a drainage port. In addition, the rivet 26, shown in FIG. 2 is replaced by a weld 26' and the crimping 31 is replaced by a weld 31 Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: j v

1. A pressure vessel comprising a rigid container having a deformable partition therein defining two chambers for fluid, said container having two ports leading respectively into said chambers, one of said chambers being adapted to receive gas under pressure and the other of said chambers being adapted to receive fluid such as oil under pressure, said port leading into said oil chamber defining an oil port of relatively large diameter, a screen assembly positioned in said oil port and extending transversely across the latter, said screen assembly comprising two juxtaposed perforated plates, one of said plates defining a support plate against which the separator is adapted to abut in operation of said pressure vessel and the other of said plates defining a base plate a portion of which is engaged by said support plate, said support plate being relatively thin as compared to said base plate, said base plate being curved and having its convex surface oriented toward said support plate, and means rigid with said container to support the periphery of said base plate.

2. The combination set forth in claim 1 in which the perforations in said support plate are of relatively small diameter as compared to the diameter of the perforations in said base plate.

3. The combination set forth in claim 1 in which said support plate is curved having its convex surface oriented toward the convex surface of said base plate.

4. The combination set forth in claim 1 in which said support plate is curved having its convex surface oriented toward the convex surface of said base plate, the centers of said plates being in engagement and secured to each other.

5. The combination set forth in claim 4 in which the centers of said plates are riveted together.

6. The combination set forth in claim 4 in which the centers of said plates are welded together.

7. The combination set forth in claim 1 in which said screen assembly comprises a sleeve of rigid material having an annular abutment surface adjacent one end of the bore thereof, the periphery of said base plate being seated on said annular abutment surface, the periphery of said support plate being secured to the sleeve adjacent its other end, said support plate being curved and having its convex surface oriented toward the convex surface of said base plate with the centers of said plates being secured together.

8. The combination set forth in claim 7 in which said annular abutment surface is beveled and the periphery of said base plate rests on said beveled surface, said base plate being secured at its periphery to the inner surface of said sleeve.

9. The combination set forth in claim 7 in which said sleeve has an annular groove in its inner surface adjacent the other end thereof, said support plate has its periphery positioned in said annular groove and said other end of said sleeve is bent inwardly securely to retain the periphery of the support plate in position.

10. The combination set forth in claim 1 in which said container has a sleeve extending from one end thereof the bore of said sleeve defining the oil port, said screen assembly comprises a sleeve of rigid material positioned in said container sleeve, said support plate being curved and having its convex surface oriented toward the convex surface of said base plate, the centers of said plates being secured together, the peripheries of said plates being secured to the inner surface of the bore of said screen assembly sleeve at longitudinally spaced positions, and means are provided releasably to retain said screen assembly in said container sleeve.

11. The combination set forth in claim 10 in which the inner end of the oil port has an inwardly extending flange defining an annular shoulder, said screen assembly sleeve is of reduced diameter at its inner end defining an outwardly extending annular shoulder adapted to abut against the shoulder defined by said annular flange, said container sleeve having an annular groove longitudinally spaced from the shoulder defined by said annular flange and a snap ring positioned in said annular groove restrains outward movement of the sleeve of said screen assembly.

12. The combination set forth in claim 11 in which the outer periphery of the outer end of the screen assembly sleeve is beveled, said beveled surface engaging said snap ring.

13. The combination set forth in claim 11 in which said screen assembly sleeve has an elongated annular groove in its outer surface defining a restraining shoulder at one end adjacent the first annular shoulder of said screen assembly sleeve, said container sleeve has a transverse threaded opening and a retaining screw positioned in said threaded opening with the inner end of said screw extending into the annular groove in said screen assembly sleeve.

14. The combination set forth in claim 13 in which said screen assembly sleeve has an elongated annular groove in its outer surface defining a restraining shoulder at one end adjacent the first annular shoulder of said screen assembly sleeve, said container sleeve has a transverse threaded opening and a retaining screw positioned in said threaded opening with the inner end of said screw extending into the annular groove in said screen assembly sleeve, the portion of the wall of said screen assembly sleeve between the secured peripheries of said plates has a passageway therethrough whereby when said screw is removed the oil in the container will bleed through the passageway and the opening in the container sleeve.

15. The combination set forth in claim 1 in which said ports are axially aligned, said deformable partition is a bladder extending axially in said container having an opening at one end secured to one of said ports and having its closed end normally spaced from said support plate, said support plate being curved having its concave surface oriented toward the closed end of said bladder and its convex surface oriented toward the convex surface of said base plate, the end of said container having the oil port having a sleeve extending axially therefrom the bore of which defines said oil port, said screen assembly comprising a rigid sleeve positioned in said container sleeve and releasably retained therein, said plates being positioned in said screen assembly sleeve and having their outer periphery secured to the inner surface of said screen assembly sleeve at longitudinally spaced positions, said screen assembly sleeve adjacent its outer end having an annular abutment surface on which the periphery of said base plate is seated.

16. As an article of manufacture, a screen assembly for the oil port of a pressure vessel, of the type having a deformable partition therein, said screen assembly comprising a sleeve of rigid material having an annular abutment surface formed adjacent one end thereof on the inner surface of the sleeve, a pair of juxtaposed plates positioned in said sleeve, one of said plates defining a support plate and the other of said plates defining a base plate, said two plates being curved, the periphery of said base plate being seated on said annular abutment surface, means to secure the periphery of said support plate to said sleeve adjacent the other end thereof, said support plate having its convex surface oriented toward the convex surface of said base plate with the centers of said plates being in engagement, both of said plates having perforations therethrough.

17. The combination set forth in claim 16 in which said support plate is relatively thin as compared to said base plate and the perforations in said support plate are of relatively small diameter as compared to the diameter of the perforations in said base plate. 

1. A pressure vessel comprising a rigid container having a deformable partition therein defining two chambers for fluid, said container having two ports leading respectively into said chambers, one of said chambers being adapted to receive gas under pressure and the other of said chambers being adapted to receive fluid such as oil under pressure, said port leading into said oil chamber defining an oil port of relatively large diameter, a screen assembly positioned in said oil port and extending transversely across the latter, said screen assembly comprising two juxtaposed perforated plates, one of said plates defining a support plate against which the separator is adapted to abut in operation of said pressure vessel and the other of said plates defining a base plate a portion of which is engaged by said support plate, said support plate being relatively thin as compared to said base plate, said base plate being curved and having its convex surface oriented toward said support plate, and means rigid with said container to support the periphery of said base plate.
 2. The combination set forth in claim 1 in which the perforations in said support plate are of relatively small diameter as compared to the diameter of the perforations in said base plate.
 3. The combination set forth in claim 1 in which said support plate is curved having its convex surface oriented toward the convex surface of said base plate.
 4. The combination set forth in claim 1 in which said support plate is curved having its convex surface oriented toward the convex surface of said base plate, the centers of said plates being in engagement and secured to each other.
 5. The combination set forth in claim 4 in which the centers of said plates are riveted together.
 6. The combination set forth in claim 4 in which the centers of said plates are welded together.
 7. The combination set forth in claim 1 in which said screen assembly comprises a sleeve of rigid material having an annular abutment surface adjacent one end of the bore thereof, the periphery of said base plate being seated on said annular abutment surface, the periphery of said support plate being secured to the sleeve adjacent its other end, said support plate being curved and having its convex surface oriented toward the convex surface of said base plate with the centers of said plates being secured together.
 8. The combination set forth in claim 7 in which said annular abutment surface is beveled and the periphery of said base plate restS on said beveled surface, said base plate being secured at its periphery to the inner surface of said sleeve.
 9. The combination set forth in claim 7 in which said sleeve has an annular groove in its inner surface adjacent the other end thereof, said support plate has its periphery positioned in said annular groove and said other end of said sleeve is bent inwardly securely to retain the periphery of the support plate in position.
 10. The combination set forth in claim 1 in which said container has a sleeve extending from one end thereof the bore of said sleeve defining the oil port, said screen assembly comprises a sleeve of rigid material positioned in said container sleeve, said support plate being curved and having its convex surface oriented toward the convex surface of said base plate, the centers of said plates being secured together, the peripheries of said plates being secured to the inner surface of the bore of said screen assembly sleeve at longitudinally spaced positions, and means are provided releasably to retain said screen assembly in said container sleeve.
 11. The combination set forth in claim 10 in which the inner end of the oil port has an inwardly extending flange defining an annular shoulder, said screen assembly sleeve is of reduced diameter at its inner end defining an outwardly extending annular shoulder adapted to abut against the shoulder defined by said annular flange, said container sleeve having an annular groove longitudinally spaced from the shoulder defined by said annular flange and a snap ring positioned in said annular groove restrains outward movement of the sleeve of said screen assembly.
 12. The combination set forth in claim 11 in which the outer periphery of the outer end of the screen assembly sleeve is beveled, said beveled surface engaging said snap ring.
 13. The combination set forth in claim 11 in which said screen assembly sleeve has an elongated annular groove in its outer surface defining a restraining shoulder at one end adjacent the first annular shoulder of said screen assembly sleeve, said container sleeve has a transverse threaded opening and a retaining screw positioned in said threaded opening with the inner end of said screw extending into the annular groove in said screen assembly sleeve.
 14. The combination set forth in claim 13 in which said screen assembly sleeve has an elongated annular groove in its outer surface defining a restraining shoulder at one end adjacent the first annular shoulder of said screen assembly sleeve, said container sleeve has a transverse threaded opening and a retaining screw positioned in said threaded opening with the inner end of said screw extending into the annular groove in said screen assembly sleeve, the portion of the wall of said screen assembly sleeve between the secured peripheries of said plates has a passageway therethrough whereby when said screw is removed the oil in the container will bleed through the passageway and the opening in the container sleeve.
 15. The combination set forth in claim 1 in which said ports are axially aligned, said deformable partition is a bladder extending axially in said container having an opening at one end secured to one of said ports and having its closed end normally spaced from said support plate, said support plate being curved having its concave surface oriented toward the closed end of said bladder and its convex surface oriented toward the convex surface of said base plate, the end of said container having the oil port having a sleeve extending axially therefrom the bore of which defines said oil port, said screen assembly comprising a rigid sleeve positioned in said container sleeve and releasably retained therein, said plates being positioned in said screen assembly sleeve and having their outer periphery secured to the inner surface of said screen assembly sleeve at longitudinally spaced positions, said screen assembly sleeve adjacent its outer end having an annular abutment surface on which the periphery of said base plate is seated.
 16. As an article of manufacture, a screen assembly for the oil port of a pressure vessel, of the type having a deformable partition therein, said screen assembly comprising a sleeve of rigid material having an annular abutment surface formed adjacent one end thereof on the inner surface of the sleeve, a pair of juxtaposed plates positioned in said sleeve, one of said plates defining a support plate and the other of said plates defining a base plate, said two plates being curved, the periphery of said base plate being seated on said annular abutment surface, means to secure the periphery of said support plate to said sleeve adjacent the other end thereof, said support plate having its convex surface oriented toward the convex surface of said base plate with the centers of said plates being in engagement, both of said plates having perforations therethrough.
 17. The combination set forth in claim 16 in which said support plate is relatively thin as compared to said base plate and the perforations in said support plate are of relatively small diameter as compared to the diameter of the perforations in said base plate. 